Question

16 Vitamin D is soluble in fat, but insoluble in water. It is present in the fat component of foods

that we eat.
-1
a Use this information to suggest how bile helps us to absorb vitamin D from food.
b Suggest into which part of the villi it is absorbed. Explain your suggestion.

Answer 1

Step-by-step explanation:

a Bile is a fluid produced by the liver that helps to break down and digest fatty foods, such as those containing Vitamin D. Bile helps to emulsify the fat in these foods, meaning that it helps to break it down into smaller droplets, which can then be more easily absorbed by the villi in the small intestine.

b Vitamin D is fat-soluble, so it is most likely absorbed into the fat-containing cells of the villi. The villi are small finger-like projections in the small intestine that have a brush-like surface, which increases the surface area for absorption of nutrients. The Vitamin D is likely taken up into the cells of the villi, from where it can enter the bloodstream and be distributed to different parts of the body.

Answer 2

Bile helps in the absorption of vitamin D by emulsifying fats, allowing them to form micelles for absorption in the small intestine. Fat-soluble vitamins like vitamin D are then absorbed into the lymphatic system within the villi through chylomicrons.

Step-by-step explanation:

Vitamin D is soluble in fat but insoluble in water and it aids in the absorption of dietary vitamin D from food with the help of bile. Bile acts as an emulsifying agent that breaks down large fat molecules, including vitamin D, into smaller molecules which form into micelles. These micelles then allow fat-soluble vitamins and lipids to be absorbed across the intestinal epithelium.

Within the villi of the small intestine, vitamin D and other fat-soluble vitamins (A, D, E, K) are absorbed into the lymphatic system rather than directly into the blood. This is because they are incorporated into the chylomicrons (small lipid transport particles) and enter the lymph vessels known as lacteals that are present in the villi, eventually making their way into the bloodstream.